A more thorough explanation:

A mass meeting is a gathering of people who come together to discuss or act on matters of common interest. It is usually open to anyone interested in the issue or purpose being discussed.

For example, a group of concerned citizens may organize a mass meeting to discuss a proposed development project in their community. The meeting would be open to anyone who wants to voice their opinion or learn more about the project.

Another example is a political campaign rally, where a candidate holds a mass meeting to rally supporters and gain new ones. The meeting would be open to anyone who wants to hear the candidate's message and show their support.

Overall, a mass meeting is a way for people to come together and have their voices heard on important issues that affect them and their community.